| Summary: | 碩士 === 國立中央大學 === 環境工程學系 === 84 === For open and dynamic systems, the conventional steady-
state control strategies applied in wastewater treatment
plants usually could not result in the best performance.
From recent research results, it has been found that the
breakpoint of the ORP and pH monitorning curves of biological
treatment processes are correlated to the disappearance of
nitrogen compound. Therefore, a real-time control strategy built
by ORP and pH was used to control the single tank continuous-
flow SBR in this study. The experimental procudures of
this study contain two main sections as follows: (1)
Fixed-time control study: to prove the feasibility of
using ORP and pH as the control parameters under
different operation conditions. Results obtained from fixed-time
studies reflect that the ORP and pH profiles can represent the
system''s dynamic characteristics, especially in pointing out
the ends of nitrification and denitrification in form of
breakpoint. It is noted that the locations and values of
ORP and pH, on those endpoints, are highly correlated to
F/M ratio with linear relationship. This result provided the
primary ideas for set-point and set-time control. The
breakpoints, set- point and set-time on the ORP and pH
profiles were used to establish the real-time control
strategy; (2) Real-time control study: some results had found
in real-time study including: (a) pH was more appropriate
parameter for controlling aerobic stage and ORP for
controlling anoxic stage; (b) six mathematical calculation
methods were appliced to determine the transfers of
operation stages, and the multiplication of two slopes of
ORP was appropriate for determining the breakpoint on ORP
profile, and the differential of pH was more practical for
determining the breakpoint of pH; (c) The real-time control
study show a good proformane in COD and nitrogen removeal,
approxicaty 93% COD , 88.68% NH4+-N, 86.54% T-N be reducted.
In addition, the real-time study required less retention
time than fixed-time study, it is approxicately 2.5 hours
can be abridged. Thus, it can save the cycle time and
aeration energy.
|
|---|
